Device and method for packaging of flat objects

ABSTRACT

A method for packaging flat objects ( 5 ) that includes the steps of completely wrapping successive flat objects ( 5 ) with a film wrapping ( 6 ) by means of a film wrapping unit ( 1 ), gripping the completely wrapped flat objects ( 5 ) each with a gripper ( 4 ) of a first conveying device ( 2 ), transporting the wrapped flat objects ( 5 ) by means of the first conveying device ( 2 ) to a shrinking unit ( 3 ), wherein the shrinking unit ( 3 ) is spatially separated from the film wrapping unit ( 1 ), and shrinking the film wrappings ( 6 ) onto the flat objects ( 5 ) by means of the shrinking unit ( 3 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a device and a method for packaging of flat objects, in particular of flat, bendable printed products, according to the generic term of the corresponding independent claims.

2. Description of Related Art

Devices for packaging of flat objects, in particular e.g. newspapers, magazines, etc., into a plastic sheet or film are generally known, e.g. from EP 1 751 005. With film-wrapped printed products such as magazines manufactured in this manner, the problem arises of supplementary products enclosed with the magazine sliding around inside the film such that their position is not defined. If such film-wrapped objects are stacked, they may slip in relation to one another such that the stack becomes unstable and difficult to handle.

EP 0 397 580 shows a handling device for bottles, which arrive in the device partly wrapped with shrink film. Grippers for holding the transported bottles are provided, which are designed for pivoting the bottles into a horizontal position. For this purpose, the bottles must be stiff and they cannot be gripped in the region in which they are covered by the shrink film. The pivoting of the bottle into the horizontal position is necessary in order for the bottle to be heated regularly and longitudinally when entering a heating channel for shrinking on the shrink film.

DE 26 10 051 also discloses a handling device for bottles, which are partly wrapped with a shrink film. A specially shaped nozzle installation effects a selective shrinking of a shrink film in a first region, such that the shrink film, when transported further, is fixed for complete shrinking on.

In both DE 26 10 051 and EP 0 397 580 the bottle is not completely wrapped by the shrink film, because on the one hand this contradicts the function of the shrink film with relation to the bottle, and in particular the shrink film covering the bottle's opening would seal the bottle there, which is not permissible.

EP 01718 198 shows a packaging device for manufacture of a shrink film wrapping and with subsequent shrinking but without the transporting of objects by means of grippers.

BRIEF SUMMARY OF THE INVENTION

It is, thus, the object of the invention to create a device and a method for packaging of flat objects of the named kind, which removes the above named disadvantages. A further object is to create a method for packaging of flat, bendable objects, which does not deform the flat objects.

This object is achieved by a device and a method for packaging of flat objects with the characteristics of the corresponding independent claims. The method for packaging of flat objects, in particular of flat, bendable printed products, includes the following steps:

-   -   completely wrapping successive flat objects with a film wrapping         by means of a film wrapping unit;     -   gripping completely wrapped flat objects (for which purpose they         are individualised, or separated) each with a gripper of a first         conveying device;     -   transporting the wrapped flat objects by means of the first         conveying device to a shrinking unit, wherein the shrinking unit         is spatially separated from the film wrapping unit;     -   shrinking the film wrappings onto the flat objects by means of         the shrinking unit.

The flat objects are thus are (indirectly) gripped through the wrapping.

The device for packaging of flat objects correspondingly includes: a film wrapping unit for wrapping of succeeding flat objects with a film wrapping; a first conveying device for gripping the completely wrapped flat objects each with a gripper and for transporting the completely wrapped flat objects to a shrinking unit, wherein the shrinking unit is spatially separated from the film wrapping unit; wherein the shrinking unit is designed for shrinking the film wrappings onto the flat objects.

Thus, it becomes possible to spatially separate the film wrapping unit from the shrinking unit, due to which again a more flexible design of the system becomes possible. For example, the distance between the film wrapping unit and the shrinking unit is at least 2 meters or at least 10 meters. Furthermore, it also becomes possible to subsequently equip an installation with a shrinking unit by integrating it into a consisting transport line.

When shrinking the film wrappings onto the flat objects, either the flat objects are held and transported by means of the grippers of the first conveying device, preferably in a vertically hanging position, or they are handed over to a second conveying device before the shrinking of the film wrappings. While shrinking the film wrappings, the flat objects are transported by means of the second conveying device. Thus, it is possible to adapt the second conveying device to constructional conditions of the shrinking unit and/or to prevent a detrimental strain on the first conveying device caused by the shrinking unit.

Preferably, after shrinking, the flat objects are transferred back from the second conveying device to the first conveying device. The transferring of the flat objects from the first to the second conveying device is preferably laid out such that it may be switched on and off. Thus it is possible to lead only individual chosen flat objects into the shrinking unit and not to subject the remaining flat objects to shrinking. With an increasing individualisation of printed products this makes it possible to individually respond to the necessity of a shrinking depending on the number or the size of the object and of the supplements.

In a preferred embodiment of the invention, an excess size of the not yet shrunken film wrappings and the parameters of the shrinking (in particular time and temperature) are matched such that the film wrapping after shrinking is free of tensile stress, i.e. that a tensile stress in the film wrapping is substantially zero. Thus, it is prevented that a flexible printed product is contracted by the tensile stress of the film wrapping and is bent or crimped.

In a preferred embodiment of the invention the conveying device runs in at least one section between the film wrapping unit and the shrinking unit on a course above head height and/or is fastened to a ceiling of a building. The conveying device, thus, runs at least 2 to 3 meters above ground level. Thus, the conveying device is arrangeable such that it does not collide with other units or passages. Preferably, the shrinking unit is hereby also arranged above head height and/or on a ceiling of a building. Thus, an even more space-saving design of the installation is made possible.

In an alternative preferred embodiment of the invention, the shrinking unit is arranged below head height and the first conveying device or a second conveying device conveys the flat objects from the height above head height to the height below head height. Thus, the accessibility of the shrinking unit is improved, though more space is required.

Further preferred embodiments emanate from the dependent claims. Hereby, the characteristics of the method claims and those of the device claims may be correspondingly combined.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the object of the invention is explained in more detail on the basis of preferred embodiment examples, which are shown in the enclosed drawings. Hereby, in a schematic manner:

FIG. 1 shows an overview of a device according to the invention;

FIGS. 2 and 3 show further variants for feeding a shrinking unit; and

FIGS. 4 a and 4 b show an object wrapped in film before and after shrinking.

The reference numerals in the drawings and their denotations are summarized in the list of reference numerals. In the figures identical parts are basically denoted with identical reference numerals.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an overview of a device according to the invention. A film wrapping unit 1 is installed for wrapping a sequence of flat objects 5. These are subsequently completely wrapped by a film wrapping 6, transported by grippers 4 of a first conveying device 2 to a shrinking unit 3 and through the shrinking unit 3.

The shrinking unit 3 heats the film wrapping for shrinking, e.g. by means of thermal radiation or by means of heated air, which is heated by means of electric energy or gas or oil and blown onto the wrapped flat objects 5.

In FIG. 1 the shrinking unit 3 is shown arranged above head height. FIG. 2 shows a further variant for feeding a shrinking unit 3, in which the shrinking unit 3 is mounted at ground level and the first conveying device 2 is lead from a course above head height back down to the height of the shrinking unit 3.

In FIGS. 1 and 2, the first conveying device transports the flat objects 5 with the grippers 4 through the region of the shrinking unit 3. Hereby, the shrinking unit 3 is preferably designed to heat the flat objects 5 and the film wrapping 6 to a lesser degree in the region of the grippers 4 than in other regions of the flat objects 5 or the film wrapping 6.

In a preferred embodiment of the invention, the shrinking unit 3 itself comprises additional gripping means or retainers 4′ (shown diagrammatically and in broken lines). These are arranged and activated for intermittent holding and transporting of the flat objects 5. The additional retainers 4′ hold and transport the flat objects 5 for a determined length of time in a transport section of the shrinking unit 3 synchronously with the grippers 4. The additional retainers 4′ e.g. hold the objects 5 from one or from both sides or from above, but next to the gripper 4. The gripper 4 of the conveying device 2 temporarily releases the flat objects 5 within this length of time. Thus, it is possible to better expose the sections of film 6 held and covered by the grippers 4 to the heat of shrinking unit 3 and to shrink them.

FIG. 3 shows a second variant for feeding a shrinking unit. In this variant a second conveying device 7 is arranged for transporting of the flat objects 5 through the region of the shrinking unit 3. A transfer device 9 is arranged for transferring the flat objects 5 from the first conveying device 2 to the second conveying device 7 and a pick-up device 10 for taking up the flat objects 5 onto the first conveying device 2 from the second conveying device 7. The second conveying device 7, thus, forms a bypass 8 or detour from the first conveying device 2 through the shrinking unit 3. The second conveying device e.g. comprises a conveying belt 11 for transport of the flat objects through the shrinking unit.

In a preferred embodiment of the invention, the conveying belt 11 is followed by a further conveying means, in particular a further conveying belt 11′, which transports the flat objects 5 further. In addition, a switchable diverting device may be provided, which, selectively guides the stream of conveyed objects 5 back to the conveying device 2 or leaves them on the further conveying belt 11′.

Preferably, the transfer device 9 may be switched on and off, wherein when the transfer is switched on the flat objects 5 are transferred to the second conveying device 7 and when the transfer is switched off the flat objects 5 are transported onward by the first conveying device 2. The switching on and off of the transfer device 9 is coupled to a coordinated, i.e. delayed in correspondence to the transport speed, switching on and off of the grabbing device 10.

FIGS. 4 a and 4 b show a film wrapped object 5 held by a gripper 4 before and after shrinking. In FIG. 4 a the film 6 lies relatively loosely around the object 5. In FIG. 4 b the film 6 is shrunk onto the object 5 and lies tightly around it, preferably with little tension, such that a bendable object 5 is not bent by the tension of the film 6.

REFERENCE NUMERALS

-   1 film wrapping unit -   2 conveying device -   3 shrinking unit -   4 gripper -   4′ additional retainers -   5 flat object -   6 film -   7 second conveying device -   8 bypass -   9 transfer device -   10 pick-up device -   11 conveying belt -   11′ second conveying belt 

1. A method for the packaging of flat objects (5), in particular flat, bendable printed products, the method comprising the following steps: completely wrapping successive flat objects (5) with a film wrapping (6) by means of a film wrapping unit (1); gripping the completely wrapped flat objects (5) with one respective gripper (4) of a first conveying device (2); transporting the wrapped flat objects (5) by means of the first conveying device (2) to a shrinking unit (3), wherein the shrinking unit (3) is spatially separated from the film wrapping unit (1); shrinking the film wrappings (6) onto the flat objects (5) by means of the shrinking unit (3).
 2. The method according to claim 1, wherein when shrinking the film wrappings (6) onto the flat objects (5), the flat objects (5) are held and transported by the grippers (4), preferably in a vertically hanging position.
 3. The method according to claim 1, wherein before shrinking the film wrappings (6) the flat objects (5) are transferred to a second conveying device (7) and when shrinking the film wrappings (6) the flat objects (5) are transported by means of the second conveying device (7).
 4. The method according to claim 3, wherein after shrinking the flat objects (5) are transferred to the first conveying device (2) by means of the second conveying device (7).
 5. The method according to claim 4, wherein the transfer of the flat objects (5) from the first conveying device (2) may be switched on and off selectively, wherein, when the transfer is switched on, the flat objects (5) are transferred to the second conveying device (7) and after shrinking again transferred to the first conveying device (2), and when the transfer is switched off, the flat objects (5) are transported onward by the first conveying device (2).
 6. The method according to claim 3, wherein the second conveying device (7) comprises a conveying belt for transporting the flat objects (5) through the shrinking unit (3).
 7. The method according to claim 1, wherein an excess of the not-shrunk film wrapping (6) and the parameters of the shrinking are matched to each other such that a tensile stress in the film wrapping is substantially zero after shrinking.
 8. A device for the packaging of flat objects (5), in particular flat, bendable printed products, comprising a film wrapping unit (1) for complete wrapping of a sequence of flat objects (5) with a film wrapping (6); a first conveying device (2) for gripping completely wrapped flat objects (5) each with a gripper (4) and for transporting the completely wrapped flat objects (5) to a shrinking unit (3), wherein the shrinking unit (3) is spatially separated from the film wrapping unit (1); wherein the shrinking unit (3) is designed for shrinking of the film wrappings (6) onto the flat objects (5).
 9. The device according to claim 8, wherein the conveying device (2) in at least one section between the film wrapping unit (1) and shrinking unit (3) runs on a course above head height and/or is fastened to a ceiling in a building.
 10. The device according to claim 9, wherein the shrinking unit (3) is arranged above head height and/or on a ceiling of a building.
 11. The device according to claim 9, wherein the shrinking unit (3) is arranged below head height and the first conveying device (2) or a second conveying device (7) conveys the flat objects (5) from above head height to below head height.
 12. The device according to claim 8, wherein the first conveying device (2) transports the flat objects (5) with the grippers (4) through the region of the shrinking unit (3).
 13. The device according to claim 8, further comprising a second conveying device (7) for transporting the flat objects (5) through the region of the shrinking unit (3).
 14. The device according to claim 13, further comprising a transferring device (9), which can be switched on and off, for transferring the flat objects (5) from the first conveying device (2) to the second conveying device and a pick-up device (10) for picking up of the flat objects by means of the first conveying device (2) from the second conveying device (7).
 15. The device according to claim 8, wherein the shrinking unit (3) for shrinking the film wrapping (6) is heated, by means of thermal radiation or by means of air heated by electric energy or gas or oil.
 16. The device according to claim 12, wherein the shrinking unit (3) for shrinking the film wrapping (6) is heated, by means of thermal radiation or by means of air heated by electric energy or gas or oil, and wherein the shrinking unit (3) is designed to heat the flat objects (5) and the film wrapping (6) in the region of the gripper (4) to a lesser degree than in other regions of the flat objects (5) and the film wrapping (6) respectively.
 17. A shrinking unit (3) for use in a device according to claim 8, comprising a section of a conveying device (2) for transporting of flat objects (5) by retaining them in grippers (4) and means for heating these transported objects (5) in the region of the shrinking unit.
 18. The shrinking unit (13) according to claim 17, comprising additional retainers (4′) for intermittent holding of the flat objects (5) in a transport section in the shrinking unit (3), during an intermittent release of the flat objects (5) by the grippers (4). 